\begin{equation*}
  f(X) = \int_{-\infty}^{X} p(X)~dX =
  \begin{cases}
    0, & X < -1 \\
    \frac{X + 1}{2}, & -1 < X < 1, \\
    1, & \text{caso contrário}
  \end{cases}
\end{equation*}

one
    two three four one
    two three four one
    two three four \test{test
  five six seven
eight nine} ten eleven
twelve thirteen
    fourteen fifteen sixteen seventeen
